pH-Responsive Chitosan-Doped ZnO Hybrid Hydrogels for the Encapsulation of Bioactive Compounds in Aquaculture.

In this study, we synthesized and characterized pH-responsive Chitosan-AgCl-doped ZnO hybrid hydrogels and evaluated their potential for loading aquaculture bioactive compounds, and assessed their antimicrobial properties against a threatening pathogen associated with disease across a broad spectrum of warm water fish and invertebrates. Hydrogel characterization consisted of assessing morphology via SEM, composition via EDS, hydrogels' network components interactions via FT-IR and pH response through swelling behavior determinations. The swelling characterization of the synthesized hydrogels demonstrated a pH-responsive behavior, showing that low pH values caused the hydrogel polymeric network to expand and capture more of the aqueous solution. These characteristics make the synthesized hydrogels suitable for the encapsulation and controlled release of drugs and bioactive compounds in aquaculture. Chitosan_ZnO hybrid hydrogels showed great antimicrobial activity against Vibrio harveyi, even better than that of loaded PB hydrogels. Here, we provide evidence for the potential capacity of Chitosan_ZnO hybrid hydrogels for the preventive and curative treatment of diseases that impact aquaculture animal health and prevent drug resistance by bacteria.

Relación entre hipotiroidismo y síndrome de ovario poliquístico / The relationship between hypothyroidism and polycystic ovary syndrome

INTRODUCCIÓN: Se ha documentado la asociación del síndrome de ovario poliquístico con alteraciones metabólicas y enfermedades cardiovasculares. Su relación con trastornos autoinmunitarios no está claramente establecida, pero se ha encontrado una importante prevalencia de desórdenes tiroideos en pacientes con síndrome de ovario poliquístico. OBJETIVO: Describir las diferentes teorías existentes que puedan explicar la relación entre hipotiroidismo y síndrome de ovario poliquístico, junto con su posible impacto en la morbilidad asociada. Método: Se realizó una búsqueda en PubMed y LILACS con las palabras clave "Polycystic ovary síndrome", "Hypotyroidism", "thyroid disease" y sus respectivos términos en español, durante julio de 2020. Resultados: Se seleccionaron 51 artículos relacionados con el tema, publicados en los últimos 10 años. La fisiopatogenia entre ambos trastornos no está claramente establecida. Se ha encontrado un importante impacto metabólico en este grupo de pacientes y se considera que su riesgo cardiovascular podría estar aumentado. CONCLUSIONES: Al considerarse la prevalencia significativa y las complicaciones que tanto a corto como a largo plazo podrían tener las mujeres con ambas alteraciones, se hace necesario discutir la necesidad de la exclusión del hipotiroidismo de los criterios diagnósticos aplicados para el síndrome, la tamización temprana y el estudio de las implicaciones terapéuticas que trae su abordaje.

INTRODUCTION: The association of polycystic ovary syndrome with other metabolic disorders and cardiovascular diseases has been documented; nevertheless, its relationship with autoimmune disorders is not clearly established, however, an important prevalence of thyroid disorders has been found in this group of patients. OBJECTIVE: To describe the different existing theories that can explain the relationship between hypothyroidism and polycystic ovary syndrome along with its possible impact on associated morbidities. Method: A search was conducted in PubMed and LILACS with the keywords of "Polycystic ovary syndrome", "Hypothyroidism", "Thyroid disease" and with its respective Spanish terms, in July 2020. Results: 51 articles related to the subject were selected, published in the last 10 years. The pathogenesis between both disorders is not clearly established. An important impact has been found at the metabolic level in this group of patients and it is considered that their cardiovascular risk could be increased. CONCLUSIONS: Considering the significant prevalence and complications that both short and long term, women with both alterations could have, it is necessary to discuss the need for the exclusion of hypothyroidism from the diagnostic criteria applied for the syndrome, early screening of the syndrome, and the study of the therapeutic implications that its approach brings.

N-Doped carbon nanotubes enriched with graphitic nitrogen in a buckypaper configuration as efficient 3D electrodes for oxygen reduction to H2O2.

Herein, a series of N-doped carbon nanotube (CNx) samples were obtained by modifying the synthesis temperature. Consequently, the proportion of graphitic nitrogen (Ngraph) in the samples was systematically increased as a function of temperature. This allowed evaluation of the role of the CNx graphitic nitrogen in the oxygen reduction reaction (ORR). A correlation between the Ngraph content and the ORR onset potential was observed, which shifted to more positive potentials with an increase in kinetic current density (jk); this showed that Ngraph played a significant catalytic role in the ORR. The samples with high Ngraph content favored the two-electron pathway for the ORR not only in basic media (pH = 13) but also in neutral media (pH = 7), representing an attractive alternative for wastewater remediation through the on-site generation of H2O2. The energetic calculations showed that the formation of H2O2 must be favorable in the presence of graphitic nitrogen sites. Finally, the performance of the buckypaper arrangement was evaluated, and the CNx buckypaper showed a higher cathodic current peak as compared to CNx traditional ink dispersions. Overall, this study not only sheds light on the role of Ngraph in the ORR, but also demonstrates that CNx buckypaper is an efficient 3D electrode for electrocatalytic applications.

Dual-photosensitizer coupled nanoscintillator capable of producing type I and type II ROS for next generation photodynamic therapy.

The current photodynamic therapy (PDT) is majorly hindered by the shallow penetration depth and oxygen dependency, limiting its application to deep-seated solid hypoxic tumors. Thus, it is meaningful to develop efficient X-ray mediated PDT system capable of generating reactive oxygen species (ROS) under both the normoxic and hypoxic conditions. Herein, we report the synthesis and characterization of nanocomposite, YAG:Pr@ZnO@PpIX with an amalgamation of UV-emitting Y2.99Pr0.01Al5O12 (YAG:Pr) nanoscintillator, and zinc oxide (ZnO) and protoporphyrin IX (PpIX) as photosensitizers. YAG:Pr surface was coated with a ZnO layer (∼10 nm) by atomic layer deposition, and then PpIX was covalently conjugated via a linker to give YAG:Pr@ZnO@PpIX. The photo- and cathodoluminescence analyses gave the evidences of efficient energy transfer from YAG:Pr to ZnO at ∼320 nm, and YAG:Pr@ZnO to PpIX at Soret region (350-450 nm). The nanohybrid was able to produce both, Type I and Type II ROS upon direct and indirect photoactivation with UV365nm and UV290nm, respectively. In vitro cytotoxicity of non-activated YAG:Pr@ZnO@PpIX in mouse melanoma cells revealed low toxicity, which significantly enhanced upon photoactivation with UV365nm indicating the photokilling property of the nanohybrid. Overall, our preliminary studies successfully demonstrate the potential of YAG:Pr@ZnO@PpIX to overcome the limited penetration and oxygen-dependency of traditional PDT.

Blue light triggered generation of reactive oxygen species from silica coated Gd3Al5O12:Ce3+ nanoparticles loaded with rose Bengal.

This data article provide results of the studies conducted to develop a mesoporous silica coated Gd2.98Ce0.02Al5O12 nanoparticles loaded with a photosensitizer dye rose Bengal (RB) system (GAG@mSiO2@RB) capable of producing reactive oxygen species (ROS) upon exposure to blue light. The data reported here is related with Jain et al. (2018) [1]. It contains histogram of particle size distribution, cathodoluminescence (CL), photoluminescence spectra and there spectral overlap with the absorption spectra of RB, a graph showing the loading percentage of RB at different concentrations. Moreover, the data indicating ROS generation evaluated using 1,2-diphenylisobenzofuran (DPBF) assay and the viability of MDA-MB-231 cells upon exposure with different concentration of GAG@mSiO2 nanoparticles, upon exposure with blue light is also included in the data.

Magnetic-luminescent cerium-doped gadolinium aluminum garnet nanoparticles for simultaneous imaging and photodynamic therapy of cancer cells.

Nanoparticle (NP) and photosensitizer (PS) conjugates capable of X-ray photodynamic therapy (X-PDT) are a research focus due to their potential applications in cancer treatment. Combined with X-PDT, appropriate imaging properties of the nanocomposite will make it suitable for theranostics of deep lying tumors. In this work, we describe the development of magnetic-luminescent Gd2.98Ce0.02Al5O12 nanoparticles (GAG) coated with mesoporous silica (mSiO2) and loaded with rose bengal (RB) to yield a nanocomposite GAG@mSiO2@RB capable of X-PDT. GAG nanoparticles were synthesized using the sol-gel method. The synthesized GAG nanoparticles showed a strong visible yellow emission with a quantum yield of ∼32%. Moreover, the broad emission spectra of GAG nanoparticles centered at 585 nm showed a good overlap with the absorption of RB. Upon irradiation with X-rays (55 KV), the GAG@mSiO2@RB nanocomposite produced significantly higher singlet oxygen compared with RB alone, as confirmed by the 1,2-diphenylisobenzofuran (DPBF) assay. The developed GAG@mSiO2@RB nanocomposite significantly reduced the viability of human breast cancer (MDA-MB-231) cells upon irradiation with blue light (λ = 470 nm). The calculated LC50 of GAG@mSiO2@RB nanocomposites were 26.69, 11.2, and 6.56 µg/mL at a dose of ∼0.16, 0.33 and 0.5 J/cm2, respectively. Moreover, the nanocomposite showed paramagnetic properties with high magnetic mass susceptibility which are useful for high contrast T1 weighted magnetic resonance imaging (MRI). Together with X-PDT, the paramagnetic properties of the proposed GAG@mSiO2@RB nanocomposite system are promising for their future application in simultaneous detection and treatment of deep-lying tumors.

Enhanced Degradation of Pesticide Dichlorophen by Laccase Immobilized on Nanoporous Materials: A Cytotoxic and Molecular Simulation Investigation.

Use of pesticides is usually related to overproduction of crops in order to overcome worldwide demand of food and alimentary safety. Nevertheless, pesticides are environmental persistent molecules, such as the organochlorine pesticides, which are often found in undesired places. In this work, we show that a hybrid nanomaterial (laccase-MSU-F) readily oxidizes the pesticide dichlorophen, reducing its acute genotoxicity and apoptotic effects. In order to predict chronic alterations related to endocrine disruption, we compared the calculated affinity of dichlorophen oxidized subproducts to steroid hormone nuclear receptors (NRs), using molecular simulation methods. We found a reduction in theoretical affinity of subproducts of oxidized dichlorophen for the ligand-binding pocket of NRs (∼5 kcal/mol), likewise of changes in binding modes, that suggests a reduction in binding events (RMSD values < 10 Å).

Single ZnO Nanowire-Based Gas Sensors to Detect Low Concentrations of Hydrogen.

Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H2 pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H2.

A biosensor based on Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes and graphene oxide for polyphenol detection.

The use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry. The oxidation of Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes (Lac/CN x -MWCNT) and on graphene oxide (Lac/GO) was used to measure the concentrations of catechol and catechin. Nitrogen-doped multiwalled carbon nanotubes (CN x -MWCNT) were synthesized by spray pyrolysis and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Covalently bonded hybrids with laccase (Lac/CN x -MWCNT and Lac/GO) were generated. Catalytic activity of free enzymes determined with syringaldazine yielded 14 584 UmL-1. With Lac/CN x -MWCNT at concentrations of 6.4 mmol L-1 activity was 9326 U mL-1, while enzyme activity measured with Lac/GO at concentration of 6.4 mmol L-1 was 9 234 U mL-1. The Lac/CN x -MWCNT hybrid showed higher stability than Lac/GO at different ethyl alcohol concentrations. The Lac/CN x -MWCNT hybrid can measure concentrations, not previously reported, as low as 1 × 10-8 mol L-1 by measuring the electric current responses.